Idle racing and hard/frozen brake pedal

[TomOsborne]

Well spent some quality time on the LC and checked the MAF on the vehicle. First set of terminals read in spec, the rest registered nothing. So I think it's accurate to say my MAF is toast. So that will be my next course of action. No reason to adjust the TPS with a bad MAF.... but I did get his little brother on the road.

 

[TomOsborne]

One more of little brother

 

[TomOsborne]

Been awhile folks. lots of work and progress. First the racing idle is tamed for the most part, lower than it was but still high but driveable. A tad bit sticky but mostly solid at 1600rpm. I ended up using a used MAF, about 100' of vac hose, cleaned throttle body and readjusted the TPS. This did nothing for the frozen brake pedal however. Pulled the MC and was surprised the booster wasnt frozen. The pedal was so rock like I couldnt imagine it wouldn't. Decided to replace the MS and still nothing. At least at this point I knew it was the booster and problem solved. While disconnecting the booster from the pedal I noticed my throttle cable is so frayed its down to about 2 wire strands, so as far as my high idle, THAT cant be helping. Ordering a new cable this week and I'll see what that does. I guess after that I would pull the IAC and test/clean it. Thanks for entertaining my nb questions and comments.

 

[SmokingRocks]

You have an Air Flow Meter (AFM) not a Mass Air Flow Sensor (MAF), you cannot put a MAF on your rig it won't work..


I am standing by the fact that you have a major vacuum leak on your intake side. Did you put the gasket on the throttle body when your reinstalled the throttle plate?

 

[TomOsborne]

You have an Air Flow Meter (AFM) not a Mass Air Flow Sensor (MAF), you cannot put a MAF on your rig it won't work..


I am standing by the fact that you have a major vacuum leak on your intake side. Did you put the gasket on the throttle body when your reinstalled the throttle plate?

ARGH sorry, AFM. I still get IAC, ISV, MAF, AFM, all changed around. I understand that can cause confusion for all involved and I should be more careful, and spend more time on my posts. Thanks for giving me your input throughout this thread. I have a new Felpro gasket behind the TB. I have not tried using smoke or other techniques for tracing additional leaks. Your input keeps me on track so again thank you. Any other advice you can offer is always considered valuable and appreciated @SmokingRocks

 

[Tools R Us]

... While disconnecting the booster from the pedal I noticed my throttle cable is so frayed its down to about 2 wire strands, so as far as my high idle, THAT cant be helping. ...

A worn/frayed cable can stick, hold the throttle plate partly open, if so, is never going to idle correctly. The TPS needs to be adjusted fully closed. Try disconnecting the cable at the throttle body, confirm throttle fully closed, recheck TPS adjustment, then start and see what the idle does. When the new cable is installed, it should be adjusted at WOT, hold the pedal down, adjust so the throttle just hits the WOT stop.

 

[Tools R Us]

On an OBD2 motor with a reader like and Ultra-gauge, the TPS adjustment is simple. The gauge displays TPS open percentage, needs to read, adjust to ~10-11% at idle. Just one if the reasons that OBD2 makes life easier.

 

[TomOsborne]

On an OBD2 motor with a reader like and Ultra-gauge, the TPS adjustment is simple. The gauge displays TPS open percentage, needs to read, adjust to ~10-11% at idle. Just one if the reasons that OBD2 makes life easier.

Well my OBDI is envious. I am envious. You know I bought hex bolts for the TPS, lost them, and used the old screws. So now Im paying the price from that screw up. Maybe I can find a 90 degree phillips head screw driver that would fit in there. So now you have me thinking about the throttle cable. When I say throttle cable Im talking to the pedal, just to be clear. Is one available aftermarket for a '92? Ive read through some threads that seem to point to this cable not being available. And I dont want to buy the kickdown by accident, if thats even available. BTW I left my glasses at home so I am partially blind so please excuse typos. Thanks!

 

[TomOsborne]

On an OBD2 motor with a reader like and Ultra-gauge, the TPS adjustment is simple. The gauge displays TPS open percentage, needs to read, adjust to ~10-11% at idle. Just one if the reasons that OBD2 makes life easier.

http://www.rockauto.com/en/moreinfo.php?pk=4216755&cc=1276657&jsn=8

okay this looks like it....

 

[Tools R Us]

http://www.rockauto.com/en/moreinfo.php?pk=4216755&cc=1276657&jsn=8

okay this looks like it....

Looks like the correct one. Some of the aftermarket ones are not great, but if that is all that is available?

 

[SmokingRocks]

TPS adjustment on OBD1 rigs is a little tricky if you try to follow the FSM verbatim. In a basic sense your main goal is to adjust the tps so that the ohm value as measured on your multi meter changes when the throttle plate drops to idle. When you get to this step let me know I can explain further.

Also FWIW in my experience a TPS that is even majorly maladjusted will not cause a surging engine on the OBD1 rigs.